Thanks, Daniel... I figured this one out using your tcpdump suggestion. For reference, it appears that the network routing or dns tables had an older cached reference for the IP address I was making xdmcp requests from. Thus, xdm resolved an invalid hostname for the source address and sent packets to a non-existing host.
e.g.: C:\cygwin>hostname NYC-5XB1R31.marketaxess.com C:\cygwin>XWin.exe -query nyc-hhgas.marketaxess.com nyc-hhgas:/var/log # tcpdump -i eth0 -l udp port xdmcp tcpdump: listening on eth0 17:08:51.760754 nyc-wr0vs.marketaxess.com.mice > nyc-hhgas.marketaxess.com.xdmcp: udp 7 17:08:51.790810 nyc-hhgas.marketaxess.com.xdmcp > nyc-wr0vs.marketaxess.com.mice: udp 52 (DF) 17:08:52.451785 nyc-wr0vs.marketaxess.com.mice > nyc-hhgas.marketaxess.com.xdmcp: udp 66 17:08:52.453015 nyc-hhgas.marketaxess.com.xdmcp > nyc-wr0vs.marketaxess.com.mice: udp 52 (DF) 17:08:52.453457 nyc-wr0vs.marketaxess.com.mice > nyc-hhgas.marketaxess.com.xdmcp: udp 29 17:08:54.458327 nyc-wr0vs.marketaxess.com.mice > nyc-hhgas.marketaxess.com.xdmcp: udp 29 17:08:57.113586 nyc-gwb1r31.marketaxess.com.xdmcp > 255.255.255.255.xdmcp: udp 34 17:08:58.458581 nyc-wr0vs.marketaxess.com.mice > nyc-hhgas.marketaxess.com.xdmcp: udp 29 > On Thu, 15 Apr 2004, Bailey Wier wrote: > > > I have upgraded to the X/Cygwin 6.7.0.0-4 but find that I am unable to view > > the login screen on a SuSE Linux box. Basically, the XWin window appears > > but does not show any of the KDM GUI or login on the remote server. The > > screen is simply a gray background with the 'X' cursor. > > The grey background with the X is the X server in the "default" state. You can > end up with this for any number of reasons. > > Since you're trying to get XDMCP to work here, run xdm/kdm on the SuSE box in > debug mode and check the logs. Are you getting any connections from your > Windows box at all? > > Also try to tcpdump at the SuSE box, "tcpdump -i eth0 -l udp port xdmcp" or > something. > > -- > Daniel Mikkelsen > Copyleft Software AS
